Setting foot provided with sealing means

ABSTRACT

A setting foot (1) for positioning machines, for example, on a base, comprises two setting members (2, 8) which can be mutually vertically displaced with respect to one another by a screw thread. The upper setting member (8) comprises a spherical surface, along which a bearing plate (17) with a spherical surface can slide. A first flexible sealing ring (21) may be accommodated between the lower (2) and the upper setting member (8), and, in the event of rotation of the upper setting member (8), bridges the spacing between the two setting members (2, 8). As a result, contamination of the screw thread is prevented. A second sealing ring (27) may be positioned along the outer circumference of the bearing plate (17), so that the curved surfaces are protected from the lateral penetration of dirt or moisture. A height indication (23) may be accommodated along the outer circumference of the upper or lower setting member (2, 8), which height indication can be covered by the sealing element (21). A lower O-ring (25) may also be accommodated, in order to prevent the penetration of moisture or dirt along the underside of the setting foot (1).

CROSS REFERENCE TO RELATED APPLICATION

This is the 35 USC §371 National Stage of International applicationPCT/NL97/00145 filed on Mar. 20, 1997, which designated the UnitedStates of America.

FIELD OF THE INVENTION

Setting foot provided with:

a lower setting member having a first screw thread and a centralopening,

a second setting member having, on its underside, a second screw threadwhich interacts with the first screw thread of the first setting member,and which second setting member comprises, on a top side, an upwardlyconcavely curved surface, a fastening hole extending from the curvedsurface as far as a bottom end face of the second setting member, and

a bearing plate having a convex surface which is directed towards thecurved surface of the second setting member and a throughbore whichopens onto the first fastening hole.

BACKGROUND OF THE INVENTION

A setting foot of this kind is known from the European PatentEP-B-316,283. That patent describes a setting foot by means of whichheavy machine components can be aligned accurately. In this case, thefirst setting member comprises a first ring with an internal screwthread on the inner wall of the central opening. The first ring of thesetting foot is placed on a base, for example around a fastening boltwhich extends through the central opening. The second setting member islikewise formed by a ring. The second ring engages by means of anexternal screw thread on the internal screw thread of the lower ring.The setting foot is vertically adjustable by rotating the rings withrespect to one another. A machine which is positioned on the bearingplate can be screwed against the bearing plate by means of a nut and abolt which runs from the base through the setting members. In this case,the curved surfaces of the bearing plate and the upper setting memberinteract such that the machine is aligned accurately.

A disadvantage of the known setting foot is that that part of the screwthread of the second ring which extends beyond the central opening ofthe first ring may be susceptible to contamination. As a result, afurther vertical adjustment in the course of time is made moredifficult, due to the fact that corrosion may occur or dirt may gatherin the screw thread. The possibility of reuse of the known setting footis likewise reduced as a result.

Furthermore, it has been found that that part of the curved surface ofthe upper setting member, or ring, which extends along thecircumferential edge of the bearing plate is likewise susceptible tocontamination and, as a result, may, for example, corrode.

Finally, it has been found that, in the event of a vertical adjustmentof the setting foot by rotating the upper ring, it is possible for thescrew thread of the upper ring to be rotated out of the screw thread ofthe central opening.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a setting foot whichavoids the abovementioned disadvantages.

To this end, a setting foot according to the invention is characterizedin that a flexible sealing element is positioned around the centralopening of the first setting member, which sealing element is connected,on the one hand, to the first or the second setting member and, on theother hand, interacts in a sealing manner with the other setting memberand, in the event of rotation of the setting members with respect to oneanother bridges a varying spacing between the setting members. Byproviding a flexible material which, for example, on the one hand isconnected to the upper setting member and on the other hand bearsagainst the lower setting member, and which bridges the space betweenthe upper and lower setting members, the screw thread is sufficientlyprotected from the environment. The sealing element may, for example,comprise a bellows which is connected to both the upper and the lowersetting member and the length of which changes in the event of rotationof the setting members, or may be a ring made of a flexible materialwhich is fixedly connected to one setting member and can slide freelyalong the other setting member.

A particularly advantageous setting foot, the first and the secondsetting members having essentially a cylindrical outer circumferencewith at least virtually identical external diameters, is characterizedin that the sealing element comprises a ring made of a flexible materialwhich, on the one hand, is fixedly connected to the outer circumferenceof the first or the second setting member and, on the other hand, canslide freely along the outer circumference of the other setting memberin the event of rotation of the setting members with respect to oneanother.

In this way, a very simple and efficient seal is obtained which isoperationally reliable and has a long service life. By way of example,the sealing element is fastened along the outer circumference of theupper setting member and bears in a clamping manner against the outercircumference of the lower setting member. In the event of rotation ofthe setting members, the loose lower end of the flexible sealing elementslides in an axial direction along the outer circumference of the lowersetting member, and ensures a suitable seal for any height of the secondsetting member.

In this embodiment, a height indication may advantageously be arrangedon the outer circumference of the lower or the upper setting member,which height indication can be covered by the sealing element. Theheight indication may, for example, comprise a scale calibration whichindicates how far the second setting member has rotated with respect tothe first setting member, or may comprise a stop mark which indicatesthat no further rotation of the second setting member is possiblewithout the screw thread becoming detached from that of the lowersetting member.

In a further advantageous embodiment of a setting foot according to theinvention, a second annular sealing element is, on the one hand,connected to the second setting member or to the bearing plate, in theregion of the circumferential edge of the bearing plate, and, on theother hand, bears in a sealing manner against the bearing plate oragainst the setting member. In this manner, contamination of the curvedsurface of the second setting member and the bearing plate due to thelateral penetration of moisture or dirt can be prevented, while thebearing plate remains freely mobile with respect to the second settingmember.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail with reference to theappended single FIGURE, which depicts a cross-sectional view of asetting foot according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The figure shows a cross-sectional view of a setting foot 1 comprising alower setting member or ring 2, an upper setting member or ring 8 and abearing plate 17. The lower ring 2 is provided with a central opening 4with an internal screw thread. A screw member 10 of the upper ring 8 isvertically adjustable in the central opening 4 by means of acomplementary external screw thread formed on the screw member 10. Onthe top side, the upper ring 8 is provided with an upwardly concavesurface 13. This surface interacts with a convex surface of the bearingplate 17. The bearing plate 17 and the upper ring 8 are each providedwith a respective fastening hole 20, 15, through which the setting foot1 can be fastened by means of, for example, a bolt between a base and aflange of a machine to be set. Using a suitable tool, the height of theupper ring 8 can be adjusted with respect to the lower ring 2 by meansof recesses 11, 11' in the upper ring 8. The desired vertical positionof the upper ring 8 with respect to the lower ring 2 can be locked bymeans of a securing bolt 6. A flexible sealing element 21, in the formof an annular rubber strip, is fastened in a recess along the outercircumference of the upper ring 8. In the event of rotation of the upperplate 8, the annular plastic or rubber strip 21 slides along thecylindrical outer circumference of the lower ring 2. As a result, dirtis effectively prevented from gathering in the screw thread of the screwmember 10.

A height indication 23, in the form of a scale calibration, is arrangedon the lower ring 2. By means of the sealing strip 21, the relativeposition of the upper ring 8 is indicated along the scale calibration23.

A second annular sealing element 27 is fastened along a circumferentialedge of the bearing plate 17 and bears in a clamping manner against theouter circumference of the upper ring 8. By means of the sealing element27, contamination of the curved surface 13 by external substances ormoisture is prevented, and corrosion thereof is counteracted.

The sealing elements 21 and 27 are preferably made of polyurethane witha Shore A hardness of 50-80.

Furthermore, an O-ring 25 is accommodated in a lower groove along thebottom of the lower ring 2, so that when the lower ring 2 is positionedon a flat base the central opening 4 is sealed, and moisture or dirt isprevented from contaminating the screw thread of the screw member 10from the underside.

It should be noted that the setting foot has been described withreference to an exemplary embodiment in which the upper ring 8 isprovided with an external screw thread and the lower ring 2 comprises aninternal screw thread in the central opening 4. However, the inventionalso relates to embodiments in which the outer circumference of thelower ring 2 is provided with an external screw thread and the upperring comprises an internal screw thread.

Furthermore, it is also possible to couple the sealing element 21fixedly to the lower ring 2 and to design the latter such that it can bedisplaced along the upper ring 8. In the same way, the sealing element27 may likewise be fixedly connected to the upper ring 8 and bear in asealing manner against the bearing plate 17.

What is claimed is:
 1. A setting foot comprising:a first setting memberhaving a central opening extending therethrough and being provided withan internal first screw thread; a second setting member having, on itsunderside, a second screw thread which interacts with the first screwthread of the first setting member, said second setting member having,on a top side, an upwardly concavely curved surface, and a firstfastening hole extending from the curved surface as far as a bottom endface of the second setting member; a bearing plate having a convexsurface which is directed towards the curved surface of the secondsetting member, a circumferential edge, and a through-bore which opensonto the first fastening hole; a flexible sealing element positionedaround the central opening of the first setting member, said sealingelement a) being connected to one of the first and the second settingmember, b) interacting in a sealing manner with the other settingmember, and c) in the event of rotation of the setting members withrespect to one another, bridging a varying space between the settingmembers; an annular sealing member connected to one of the secondsetting member and the bearing plate in the region of thecircumferential edge of the bearing plate, and bearing in a sealingmanner against one of the bearing plate and the second setting member;and the first setting member being provided on the underside with a sealwhich is positioned in a groove extending around the central opening. 2.The setting foot according to claim 1, wherein the first and the secondsetting members have an essentially cylindrical outer circumference withsubstantially identical external diameters; the sealing elementcomprising a ring made of a flexible material which is fixedly connectedto the outer circumference of one of the first and second settingmembers, and can slide freely along the outer circumference of the othersetting member in the event of rotation of the setting members withrespect to one another.
 3. The setting foot according to claim 2,further comprising a height indicator arranged on the outercircumference of the setting member which is not fixedly connected tothe sealing element, said height indicator structured and configured tobe covered by the sealing element.